Blue light is becoming quite of an issue in recent years. Public in the past doesn't seem to have been bothered by this blue light. Massive increase in electronic usage most importantly smartphones have motivated some researchers to do some lab work to see if that blue light can cause damage to eyes. They did some work and found out that indeed the blue light is harmful for our eyes. Moreover, it damages the cells and quite possibly can cause blindness.
Hold on there for a second, blue light is harmful and can cause blindness? So why are many people seem to be immune to it. Let's break it down
Human eyes are very delicate gift of nature and are very sensitive to the surroundings. Most importantly light. The protection from blue light is not new. Old monitors like the cathode ray tube monitors or CRTs have some flaws. It has problems like; image flickering, low resolution, low brightness, high power usage. Human eyes have to work very hard resulting in eye strain when using CRTs.
Then comes the LCDs which have better resolution best image sharpness and great brightness. It was light and inexpensive. It was that time when PC was almost considered a must have item in the house. The PC industry was booming, more and more people can now afford computer because of low prices. When more people were using computer and for long periods of time they were having issues like dry eye, eye discomfort, headache and vision problems.
Yes, the technology was relatively new and those eye problems were old. But, the idea stuck that these new LCDs causes more eye problems than their counterparts like CRTs.
The thing is that in old times the screens were not efficient. We then transitioned to the LED and it was a good alternative for general public, because they consume less power and its effect on the national grid was high.
However, it has flaws of its own. Mainly, the LED's of today are more powerful than that of early generations. Also, the LED's degenerate over time because of the bleaching of the phosphorus so, it (phosphorous) no longer absorbs the blue light. This in turn changes the color temperature of the device. Also, resulting in high blue emission of from device over time.
Normally the light with wavelength of 300nm to 700nm can be detected with human eyes but blue light with high energy and shorter wavelength between 415nm and 455nm is most dangerous.
Let's break down the blue light's effect on eyes
The first thing that light encounters is our cornea. Some studies have suggested that cornea epithelial cell's survival rate decreases after blue light encounter. Also, that the blue light is responsible for production of reactive oxygen species in cornea epithelial cells resulting in dry eyes. In another in vitro culture experiment researchers have found that near ultraviolet region blue light may affect the multiplication of cells depending on time and dosage.
Given the dose and time researchers have also find out that blue light can also cause damage to the stromal cells of cornea. However opposite to that blue light is also used to treat keratitis (caused by the bacterial infection). Combination of riboflavin and 440nm wavelength of blue light can control this disease.
The next thing light encounters is lens. Studies in 1980's have suggested that in order to reduce retinal damage the lens filter out the short wavelength lights. The lens contains structural proteins, enzymes, and protein metabolites that absorb short wave light. These substances along with derivatives work together and produce yellow pigment in lens protein and turning lens yellow. As this is happening the lens undergoes cataract formation.
Blue light's damage to retina is still being debated but it is thought that it causes retinal photochemical damage. Degradation of retinal pigment is also the victim of blue light. Also, after the blue light exposure researchers sees the rush of microglia cells in the affected part of the retina. This rush is also seen in the AMD patients. Some studies also show that blue light can advance the AMD occurrence for those who had cataract surgery.
A 24-hour blue light exposure experiment was conducted on rabbits, indicating damage to the photoreceptor cells. Moreover, a research has shown that the blue light can cause destruction of the blood retinal barrier and cause photoreceptors damage and inflammation.
Blue light can oxidize retinal mechanism, destroys messenger ribonucleic, activates free radicals in aerobic conditions. It can also cause mortification of pigment epithelial cells and photoreceptor cells.
There's a big debate on the most important aspect of the blue light's impact on circadian rhythm and there are numerous studies that backs this theory. The light does this by disturbing the activity of the melatonin hormone, thus in turn disturbing the circadian rhythm.
Some studies have also found that if the blue light is excessive it can damage retina as well as spark the brain. In the response the brain releases the corticosteroids an anti-inflammation agent that destroys the melatonin hormones.
Some researchers suggest that the sleeping disorder is related to the eye disease. They say that during screen time we tent to close eyes less leading to the dry eye. Corticosteroids are also responsible, when they are produced they reduce the tear production and this leads to dry eye and bad sleep habit.
So, after discussing all this how damaging blue light is?
As the technology is improving day by day so does the preventions against blue light's anti-agent. Smartphones, TVs and advanced computers have their screens made so that they reflect less light. So much so mobile phone apps nowadays have options to let you know to take a break.
Retina cells have also pigments that can protect us against blue light namely lutein and zeaxanthin. These two are natural blue blockers in our eyes.
Also, the most important thing to remember is that not all blue light is harmful for eyes as mentioned above the blue light is used against bacterial keratitis. Likewise, particular amount of blue light can slow the growth of eye axis, improve the circadian rhythm and also prevent the occurrence of myopia.
We should not blame the light, we should also set our routine accordingly so that we can have less blue light exposure. We can also use anti-blue light glasses and limit the use of electronic devices before bed time.
Luckily for heavy computer users and years of research scientists are able to make antioxidants for eyes and still the research is going on to make them better.
Remember, all blue light is not damaging and the tests subjects in the previous mentioned experiments are lab rats and rabbits, they have some similarities with humans but not all. And those experiments are time and dose based and these test subjects are imposed to the blue light only.
